The semiconductor integrated circuit (IC) industry has experienced exponential growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling down has also increased the complexity of processing and manufacturing ICs requiring new design and production techniques.
In particular, electrical isolation of adjacent devices is a factor affecting the design and production of devices with increasing functional density. For example, transistors that are adjacent to each other are isolated with nonconductive features such as shallow trench isolation (STI) structures. Similarly, conductive electrical lines are electrically isolated in insulating dielectric layers. As the spacing between devices has decreased, the spacing allocated for isolation features has decreased as well.